Description of the Prior Art
The density of components in electronic devices has recently rapidly increased in response to requirements toward their miniaturization. In order to increase the density of electronic circuitry, a number of designs for connectors used for connecting circuit boards have been proposed and implemented.
An example of connectors for base boards having low profile intended for connection (parallel to each other) of a pair of base boards having multiple lands arrayed on the internal (facing each other) surfaces is shown in FIG. 5. It is an elastomer connector (an elastic connecting component) manufactured by AMP Incorporated (Harrisburg, Penn., U.S.A.) and distributed under the AMPLIFLEX trademark. Another example of elastomer connectors is described in U.S. Pat. No. 4,636,018.
As can be seen from FIG. 10, a conventional elastomer connector 100 consists of a rod-shaped core 101 made of an elastomer material (insulating elastic material), such as, for example, silicone rubber, to the external surface of which ring-shaped conducting layers 102 are applied at regular intervals in a highly dense array. This elastomer connector 100 is pressed between the inner surfaces of the first and second 110, 120 base boards having multiple electrical lands or traces 111, 121 in the form of straight lines. When the lands 111, 121 are aligned and both base boards 110, 120 are pressed together, elastomer core 101 of elastomer connector 100 is deformed, thus producing connection between lands 111, 121 by means of conducting layers 102.
However, it is difficult to achieve reliable connections using such a conventional connector for base boards or an elastomer connector 100 due to the fact that the elastomer connector 100 is deformed by applying a great pressure to the base boards 110, 120 resulting in pressing the conducting layer 102 located at the circumference of the elastomer connector to the lands 111, 121 to make electric connection between them without producing wiping action. This problem becomes more serious if either of the base boards 110 or 121 is warped under the pressure making it impossible to create correct and reliable connections between all the lands.
In order to prevent the warping of the base boards 110, 120, it is necessary to maintain the distance between the base boards unchanged by securing them by several screws along the lands 111, 121. However, screws take some space, thus decreasing space available for the lands. Another disadvantage of such a solution is a substantial reduction in productivity of the assembly operations.
Another method of preventing the warping of the base boards consists in reinforcing the boards by making them thicker or in providing them with a reinforcing plate in the area of connection sections. However, if thicker boards or additional reinforcing plates are used, the overall thickness of the device will also increase, thus decreasing the density of mounting.